You can also query on them, which is really cool IMO! E.g. give me every document where the score has increased:

  r.table('games')  \
   .changes()       \
   .filter(r.row['old_val']['score'] < r.row['new_val']['score']) \
   .run(conn)

Or, give me every document for user X:

  r.table('games')  \
   .changes()       \
   .filter(r.row['new_val']['user_id'] == X) \
   .run(conn)

So you can write really cool apps out of the box without having to filter things on the client.

(BTW, we have a lot more planned for this)